The present invention relates to an electronic device and its method of manufacture and, in particular, to an electronic device such as a liquid crystal display unit and/or a cellular phone wherein the conventional light reflection tape is eliminated from the lightguide in favor of a reflection strip on the printed circuit board.
FIG. 1 illustrates a conventional liquid crystal display unit including a printed circuit board (PCB) 12, a lightguide 14, and a liquid crystal display (LCD) 16. Suitably sized reflection tape 18 is secured to the back side of the lightguide 14 for reflecting light from the PCB 12 back to the display area of the LCD 16. Some conventional constructions also secure such reflection tape 18 in the area of the keypad to increase the effectiveness of the light source.
The reflection tape 18 evenly disperses the light from diode lenses in the lightguide. Conventionally, there is provided on the PCB 12 different types of gold-plated conductors and via-holes. These conductors and via-holes can be seen through the LCD 16 in the absence of the reflection tape 18. Thus, the reflection tape 18 in the area of the LCD 16 also serves to cover the smaller gold-plated surfaces and via-holes on the PCB 12.
During assembly, affixing the reflection tape 18 to the lightguide 14 requires expensive, high-performance equipment. Because of high-volume production, often more than one assembly unit is required at a single manufacturing location. Moreover, affixing the reflection tape 18 to the lightguide 14 is an intricate process. Consequently, by eliminating the tape, the price of the lightguide can be significantly reduced. Moreover, without the reflection tape, more manufacturers will have the capability to produce the lightguides as the manufacturers need only injection mold the lightguide, and it is ready for assembly into a liquid crystal display unit for, for example, cellular phones and the like.